A wide area network (WAN) is a network which covers a large geographical area, and uses communications circuits and systems to connect the network nodes. A wide area network can comprise wired technologies, wireless technologies, or a combination thereof. “Wide area” coverage is defined by a number of fixed base stations which are typically distributed geographically over a large area and are connected over a wired network. Often these stations are distributed in such a way that no one station could cover the same geographic area by itself (however this isn't always the reason for such a wide area network). This enables a first mobile wireless radio within coverage of a first fixed base station to communicate with other (second, third, etc.) mobile wireless radios within coverage of remote fixed (second, third, etc.) base stations. Other types of units which can be on the wide area network (WAN) are console units—these are units where users can communicate to other console users as well as mobile radio users; however the console connects to the network over a wire rather than wirelessly.
Wireless wide area networks utilize communication technologies such as WIMAX (Worldwide Interoperability for Microwave Access), UMTS (Universal Mobile Telecommunications Service), GPRS (General Packet Radio Service), CDMA (Code division multiple access), GSM (Global System for Mobile communications), CDPD (Cellular Digital Packet Data), HSDPA (High-Speed Downlink Packet Access), 3G (third generation), 4G (fourth generation), Motorola's MOTOTRBO™ digital two-way radio system, and the like, to transfer data.
Within a wide area network, a variety of communication scenarios can co-exist. For example, one use of the wide area network is to enable a group call (i.e. one mobile radio user transmitting to many mobile radio users who are listening). Other examples of communication scenarios within a wide area network are a private call (i.e. one mobile radio user to one other mobile radio user), a short data call (e.g. text messaging), and an emergency call.
Peer to Peer communication (P2P) is a topology where “Peers” talk directly without go-betweens. Peer-to-peer is a communications model in which each party has the same capabilities and either party can initiate a communication session.
The Internet is a worldwide, publicly accessible series of interconnected computer networks that transmit data by packet switching using the standard Internet Protocol (IP). It is a “network of networks” that consists of millions of smaller domestic, academic, business, and government networks, which together carry various information and services.
It is desirable in some situations for a Peer to Peer (P2P) Wide Area Network (WAN) to be deployed over the Internet. For example, the P2PWAN can be composed of single frequency conventional stations connected P2P over the Internet. The “Peer” is terminated in the stations. The term Peer and station are synonymous.
In such systems, there is a requirement that the subscriber be registered on only one Peer at a time; it must also be affiliated to one Talkgroup at a time. The registration/affiliation message from a subscriber to a station, over the air (OTA), must contain at least the subscriber's identification (ID) and the talkgroup to which it desires to affiliate.
Typically, there is no control channel in the system directing subscribers to a media channel. In a P2PWAN consisting of many different stations on different outbound frequencies, media intended for that subscriber will be sent to that subscriber on only one frequency. Therefore the P2PWAN and subscriber must align to the same frequency so that the subscriber shall receive the media.
The purpose of the registration/affiliation message is to “pull” media to the one station on which the subscriber is registered/affiliated. The subscriber is “parked” on the frequency of the station on which the registration/affiliation was received, waiting for activity. If there is activity on the P2PWAN, the WAN knows on which Peer the registration/affiliation was received. All media that corresponds to the subscriber's ID in the registration message or the talkgroup in the affiliation message is then sent to that one station upon which the registration/affiliation was received. That one station upon being sent media for that one subscriber from other Peers in the P2PWAN then transmits the media outbound to the subscriber. All of this assumes there is one valid registration/affiliation on only one Peer for that one subscriber. If there is a mismatch between the frequency on which the subscriber is “parked”, the subscriber will not receive the media.
If a method of reliability isn't employed in the system, a race condition can occur; the P2PWAN may think the subscriber is parked on one Peer's frequency when actually the subscriber is parked on a different frequency. In this case, media would be routed to the wrong station, the wrong station will then either transmit the media on a frequency the subscriber isn't listening to (and therefore the subscriber doesn't get the media), or dump the media packet (and therefore the subscriber doesn't get the media), or route the audio to the station that Peer thinks is the correct Peer (and therefore the subscriber may or may not get delayed media), or inform the sending Peer, what it thinks is the correct Peer (and the subscriber may still not get the media).
Accordingly, there is a need for a method and apparatus for reliable peer to peer subscriber registration and affiliation in a P2P WAN in which the WAN is deployed over the Internet.
Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of embodiments of the present invention.
The apparatus and method components have been represented where appropriate by conventional symbols in the drawings, showing only those specific details that are pertinent to understanding the embodiments of the present invention so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein.